Phosphonate carbamates

ABSTRACT

THIS INVENTION RELATES TO PHOSPJORUS-CONTAINING CARBAMATES HAVING AT LEAST ONE N-METHYLOL OR N-ALKOXYMETHYL GROUP. THESE COMPOUNDS CAN BE USED TO IMPART DURABLE FLAME-RETARDANT PROPERTIES TO CELLULOSE-CONTAINING SUBSTRATES.

United States Patent 3,825,630 PHOSPHONATE CARBAMATES Stephen B. Sello,Cedar Grove, and Bernard J. Gaj, Montclair, N.J., assignors to J. P.Stevens & C0., Inc., New York, N X.

No Drawing. Original application June 18, 1971, Ser. No. 154,690, nowPatent No. 3,758,554. Divided and this application Apr. 30, 1973, Ser.No. 355,837

Int. Cl. C07f 9/40 US. Cl. 260-938 3 Claims ABSTRACT OF THE DISCLOSUREThis invention relates to phosphorus-containing carbamates having atleast one N-methylol or N-alkoxymethyl group. These compounds can beused to impart durable flame-retardant properties tocellulose-containing substrates.

This is a division of application Ser. No. 154,690, filed June 18, 1971,now US. Pat. 3,758,554.

The present invention relates to novel phosphoruscontaining carbamateshaving at least one reactive N- methylol or N-alkoxymethyl group.Flame-retardant properties are imparted to cellulose-containingsubstrates by reacting the carbamate compounds with cellulosic hydroxylgroups.

The phosphorus-containing carbamates of this invention have the formulaR is alkyl of 1 to carbon atoms; a is an integer equal to 3 -b; b is aninteger of 1 to 3; and Z is a radical selected from the group consistingof -R1OON CH 0 R wherein R is an alkylene radical of 1 to 5 carbonatoms; R is hydrogen, alkyl of 1 to 5 carbon atoms or -C'H2OR3; R ishydrogen or alkyl of 1 to 5 carbon atoms; and

wherein R R and R have the meanings given above; and R is an alkyleneradical of 1 to 5 carbon atoms.

Carbarnates of this invention can be prepared by reacting aphosphorus-containing alcohol of the formula where X is R OH or -R -N (ROH) and R and R have the meanings given above, with an isocyanate of theformula OCNR where R is hydrogen or alkyl of 1 to 5 carbon atoms, inpresence of a basic solvent such as pyridine whereby reaction takesplace at the -R OH groups to give -R OCONHR groups and thenmethylolating the resulting intermediate product by reaction withformaldehyde. This reaction is illustrated by the following equations inwhich the phosphorus-containing alcohol is tris- 3,825,630 Patented July23, 1974 (hydroxymethyl) phosphine oxide and the isocyanate is methylisocyanate.

o 0 ll pyridine z0 )3 3OCNCH3 rwmoooNHonoa -CHiOCON groups, where R ishydrogen or alkyl of 1 to 5 carbon atoms, and then methylolating thisintermediate with formaldehyde to obtain the desiredphosphorus-containing carbamate. These reactions are illustrated by thefollowing equations wherein the phosphorus-containing alcohol has theformula (C H O) P (0) CH N(CH CH OH 2 and ammonia is used ll(C2H50)2PCH1N(CH2OHIOH)2 20011500001 If the methylolation prooedure ofthe two above-described processes is carried out using a solution offormaldehyde in an alkanol such as methyl or ethyl alcohol and theproduct obtained is acidified e.g. with HCl, the carbamate produced hasN-alkoxymlethyl groups in place of the N-hydroxymethyl groups shown inthe above equations.

Representatives of the alcohols which are useful starting materials forthe preparation of the phosphorus-containing carbamates of thisinvention are the following compounds:

P(CH;OH);; 1) i) 2 onlomopponrmonronlomg (3) (onaomo r canon 4onaomonronicmon (5) CHaCHzO II (CHQO H);

(6) CHaCHzO 1|? (CII3CHZO H) z (7) P (CH CHz O H) 3 (8) I" (CHZCHZCIIZOH) The compounds of this invention are useful as durable flame-retardantagents for cellulose-containing substrates. The N-hydroxymethyl orN-alkoxymethyl groups react with cellulosic hydroxyl groups formingwater-insoluble cellulose ethers which contain both nitrogen and phosphorus. This reaction is carried out by heating at a temperature ofabout 60 to 200 C., preferably at 120 to 180 C., in the presence of anacidic catalyst.

Suitable acidic compounds for catalyzing the reaction of the carbamatesof this invention with cellulosic hydroxyl groups include the ammonium=or amine salts of mineral acids; the chlorides and nitrates of zinc andmagnesium; acid fluoride salts; and Zinc fluoroborate. In addition tothe above salts, non-volatile acids of moderate strength such as citricacid and sodium hydrogen sulfate can also be employed. The amount ofacidic catalyst added to the treating bath should be equal to about 0.2to 10% by weight based on the Weight of the treating bath, andpreferably from 0.3 to 4.0% by weight.

The phosphorus-containing carbamate and the acidic catalyst can beapplied from an aqueous solution or dispersion by padding, brushing,spraying, or other impregnation technique. It is preferable that afterformation of the reaction product the add-on of bound phosphorus beabout 0.5 to 4.0% by weight based on the weight of the finished product,i.e., substrate plus flame-retardant reaction product. The concentrationof the carbamate reactant in the impregnation bath and the wet pickupare adjusted to give the desired add-ons of phosphorus. The add-on ofbound nitrogen also contributes to the flameretardant properties of thetreated substrate. The amount of nitrogen in the treated product can beincreased by using one or more nitrogen-containing compounds inconjunction with the carbamates of the invention. The add-on of boundnitrogen should be about 1.0 to by weight based on the weight of thefinished product.

The phosphorus-containing carbamates can be used in conjunction with anitrogen-containing, durable-press resin such as N-hydroxymethyl orN-alkoxymethyl derivatives of non-phosphorns-containing carbamates,dimethylol urea, dimethylol alkylene urea, dimethylol dihydroxy alkyleneurea, polymethylol uron, polymethylol melamines, etc. In such cases, aportion of the nitrogen required for flame retardancy can be supplied bythe durable-press resin. The phosphorus-containing carbamate and thedurable-press resin can be applied in a single step operation or bysequential treatments with either compound being applied first. Thereaction of the durablepress with cellulose is catalyzed with the sametype of acidic catalyst used with the phosphorus-containing carbamate.

If desired, polymethylol melamine resins can be employed using a wetfixation technique so that an insoluble nitrogen-containing product isformed on the substrate with little or no reaction with the cellulose.In the wet fixation procedure (e.g., steaming) the moisture content ofthe substrate is maintained at a minimum of 10% by weight based on theweight of the substrate during the reaction of the polymethylol melamineto form an insoluble product. When the phosphorus-containing carbamateand the polymethylol melamine are applied to a farbic simultaneously, itis preferable to first steam the fabric to self-polymerize thepolymethylol melamine and then to dry heat the fabric in the presence ofan acidic catalyst to react the carbamate with cellulosic hydroxylgroups.

The cellulosic substrate to be rendered flame retardant should containat least 30 Weight percent cellulose. The substrate can be a yarn orthread, or a woven knitted or non-woven fabric.

Particularly outstanding compounds within the scope of the presentinvention which give excellent flame-retardant properties are compoundsof the formula where R R and R have the meanings given above. Anotherpreferred group of carbamate compounds within the scope of thisinvention has the formula ANALYTICAL AND TEST METHODS EMPLOYED IN THEEXAMPLES Bound Nitrogen, N in percent: Determined by Kjeldahl digestion,followed by titration of the distilled ammonia.

Bound Phosphorus, P in percent: Determined by Kjeldahl digestion,followed by colorimetric analysis employing acetone-water to intensifythe phosphomolybdate color: Bernhart et al., Anal. Chem., Vol. 27, 440,(1955).

Flame Retardancy (Vertical Test), char length in inches: AATCC 34l966. Achar length of about 6 inches or shorter is passable.

Flame Retardancy (Limiting Oxygen Index), the minimum value of thevolume fraction (expressed in decimal form) of oxygen in a meteredoxygen-nitrogen mixture, using a flammability index tester (Type FL101,General Electric Co.): C. P. Fenimore and F. J. Martin, Combustion andFlame, Vol. 10, No. 2, 135 (June 1966), and Modern Plastics, Vol. 43,No. 11, 141 (November 1966). Generally, a limiting oxygen index of about0.260 or greater is passable.

Dry Crease Recovery, total of angular degrees in warp (W) and filling(F) directions: ASTM Dl295-60T.

Flex Abrasion Resistance, in cycles: ASTM D1175- 44T (0.5-pound headweight and 2-pound toggle tension on a Stoll Flex Abrader).

Laundering: AATCC 88A-l964T, Test III, home-type washer, 5-pound load,full cycle, 60 C., synthetic detergent; tumble drying.

Tear Strength (Elmendorf), ASTM D142459.

Tensile (Breaking) Strength: (One-inch ravelled strip), in pounds: ASTMD1682--63.

ABBREVIATIONS in pounds:

OWB: On the Weight of the bath used for padding, in percent.

OWF: On the weight of the fabric, in percent.

Wet pickup (in percent) multiplied by OWB/ equals OWF (in percent).

TMM: T rimethylol melamine,(s-triazine-2,4,6-triyltriimino)-trimethanol.

BEL: Burned entire length of fabric sample in vertical flame test.

EXAMPLE 1 The compound was prepared by adding 695 grams of methylisocyanate to a suspension of 472 grams of tris-(hydroxymethyl)phosphine oxide in a mixture of 2500 ml. of benzene and 180 ml. ofpyridine at 60-70 C. followed by 2 hours at reflux. The separated solidwas crystallized from methyl alcohol to give 821 grams of product, m.p.119-l20 C.; N found: 13.49%; theory 13.5%.

A quantity of 233 grams of the above compound was stirred at roomtemperature with 200 grams of 37% aqueous formaldehyde solution at a pHof 8 9 for hours. The free formaldehyde content of the aqueous solutionwas reduced to 4.75% and there was produced the compound f) /CH3 P (CHOOON CH OH 3.

The aqueous solution of desired carbamate compound produced by themethylolation step can be neutralized with an acid such as HCl and thenused directly in the treatment of a cellulose-containing substrate.

EXAMPLE 2) Using the procedure described in Example 1, 627.5 grams ofmethyl isocyanate was added at 40-50 C. to a mixture of 1275 grams of021-150 zi ommomornomz 2000 ml. of benzene and 100 grams of pyridine,the reaction mixture was refluxed for 5 hours and stripped of solventsunder vacuo leaving a viscous liquid compound (11.43% N; theory 11.4%)having the formula -A mixture of 904 grams of the compound of the aboveformula and 169 grams of paraformaldehyde was stirred for four hours at6070 C. while maintaining a pH of 8-9 with 6N sodium hydroxide. Acompound was produced having the formula CH3 (C2Hs0)zP (O)CH2N(CH2CH:O CON CHzOH 2.

EXAMPLE 3 1252 grams of phenyl chloroformate was added to a solution of1024 grams of in 2000 ml. of pyridine while cooling in a tap water bath.The product was poured into 1200 ml. of distilled water and the layersseparated. The wash procedure was repeated several times and the residuewas dried ovr MgSO- in 1:1 benzene/chloroform and stripped of solventsleaving 1478 grams of bis(oarbonate ester) of the formula Ammonia gaswas bubbled through a 2000 ml. pyridine solution containing 1453 gramsof the above bis(carbonate ester) at 20-30" C. with cooling. When theexotherm subsided the mixture was poured into 2 liters of water and thelower layer was dried over anhydrous MgSO in 1:1 benzene/chloroform.Removal of the solvent and vacuum stripping at 90-100" C. left a mixtureof the desired intermediate compound and phenol which was separated bytreatment with dilute sodium hydroxide (10%) solution and extractionwith chloroform. Removal of the chloroform from the dried extracts gave137.5 grams of compound having the formula which were treated with 184grams of 37% aqueous formaldehyde solution at a pH 9.5-10 and atemperature of 60-70 C. for 14 hours, after which the free formaldehydecontent was 5.75%. There was produced a compound of the formula ornoH(C2HsO)2P (O)CH$N CH1CH3D C ON/ CHsOH 2. If the procedure of Example 3is repeated using as the phosphorus-containing alcohol startingmaterial, there is produced the compound Samples of the product ofExample 3, phosphoruscontaining carbamate having the following formulaCHzOH CH OH 2 were dissolved in a 2:1 dimethyl formamide/ water mixtureand either MgCl or an alkanolamine hydrochloride (AHCl) of the formulawas added as catalyst. Concentrations of the reagent and catalyst arespecified in the accompanying table.

Samples of sheeting fabric Woven from all-cotton yarn in a plain weave,weighing 4.5 ounces per square yard, were padded in the treatingsolutions with the pressure of the squeeze rolls adjusted to give a wetpickup of about -100%. The padded samples of fabric were dried in aforced draft laboratory oven at approximately 66C., then cured. Theconditions of the curing are specified in the accompanying table. Thespecimens of the fabric were washed for 15 minutes at approximately 88C. in an aqueous solution of which 0.1% was sodium carbonate and 0.1%was a non-ionic detergent (Triton X-100, a mixture of closely relatedcompounds having the formula where x has an average value of about 10).Finally, the fabric was neutralized in dilute acetic acid solution,rinsed in water, dried on a frame in a forced-draft oven and evaluated.

TABLE FOR EXAMPLE 4 Untreated Percent reagent, OWF Catalyst M Percent;catalyst, OWB Curing Weight. gain 22. 8 Percent: bound pl1osphorus*Percent bound nitrogen* Limiting oxygen index 27 *Weight. percent oftreated fabn'c.

EXAMPLE 5 at room temperature, then washed and dried. By this proceduretrimethylol melamine was insolubilized in essentially quantitativeyield.

The results of the treatment of the trimethylol melamine pretreatedsamples (Weight gain: 14.8%, N content: 4.5%) with the product ofExample 3, phosphoruscontaining carbamate having the following formula*Weight percent of treated fabric.

EXAMPLE 6 The product of Example 1, phosphorus-containing carbamatehaving the following formula CHzOH CHzO C o N was applied from a 31.0%aqueous solution containing 2% of the alkanol amine hydrochloride (AHCl)catalyst described in Example 4 to a fabric sample woven from twistedall-cotton yarn in a twill weave weighing 8 ounces per square yard. Theapplication was carried out on a laboratory padder with the pressure ofsqueeze rolls adjusted to attain 86% Wet pickup. The padded sample wasdried, cured, washed and dried as described in Example 4. The so treatedsample had a weight gain of 21.6% corresponding to 93% reaction yield.

The treated sample was after-treated with 15% aqueous trimethylolmelamine solution containing 0.3% H on a laboratory padder with thepressure of squeeze rolls adjusted to give 65% wet pickup. The samplewas dried to 20-30% moisture content, steamed in a laboratory steamerfor 8 minutes, Washed and dried. The so treated sample had an additional617% weight gain.

The results of the above applications before and after TMM treatment areshown in the accompanying table.

TABLE FOR EXAMPLE 6 Before TMM After TMM treatment treatment Percentbound phosphorus 1. 1. 4

Percent bound nitrogen 1.8 4. 3

Char length in vert. flame tes BEL 5. 5

EXAMPLE 7 trimethylol melamine, and one of the acid catalysts describedin Example 4 were applied to cotton twill fabric samples using themethod described in Example 4. The regults of the treatment are shown inthe accompanying ta le:

TABLE FOR EXAMPLE 7 Percent P containing reagent,

Tensile strength 1 stripW Tear strength, ElmendorfF Crease recovery, WF, dry Flex abr.W

*3 minutes steaming followed by 5 minutes heat curing at 163 C.

It will be apparent that many modifications and variations can beeffected without departing from the scope of the novel concepts of thepresent invention, and the illustrative details are not to be construedas imposing undue limitations on the invention.

What is claimed is:

1. A phosphorus-containing carbamate of the formula 0 01120113 (RO)ZI LR N R O-(E-N wherein R is alkyl of 1 to 5 carbon atoms; R is an alkyleneradical of 1 to 5 carbon atoms; R is hydrogen, alkyl of 1 to 5 carbonatoms or CH OR R is hydrogen or alkyl of l to 5 carbon atoms; and R isan alkylene radical of 1 to 5 carbon atoms.

2. A compound of the formula 0 0 CH3 II II (O21I50)2PCH2N CHgcH3O-CNCHQOH 2 3. A compound of the formula (I? (I? /CH2OH (CgH50)2PCHaNCHzCHzO -N\ CHzOH 2 References Cited UNITED STATES PATENTS 3,763,28310/1973 Curgan 260938 ANTON H. SUTTO, Primary Examiner US. Cl. X.R.117136; 260-968

